vp9: Don't force block size to 8x8 in denoiser.

First, we only set use_4x4_partition for key frame where we don't
denoise; second, envision we have small partitions, we should pass the
actual block size to denoiser and make an early termination if needed.

Change-Id: I331f42046d792b17360723d17ff817d601394658
diff --git a/vp9/encoder/vp9_pickmode.c b/vp9/encoder/vp9_pickmode.c
index 2e27f94..fd51598 100644
--- a/vp9/encoder/vp9_pickmode.c
+++ b/vp9/encoder/vp9_pickmode.c
@@ -1845,8 +1845,7 @@
       cpi->denoiser.denoising_level > kDenLowLow &&
       cpi->denoiser.reset == 0) {
     VP9_DENOISER_DECISION decision = COPY_BLOCK;
-    vp9_denoiser_denoise(cpi, x, mi_row, mi_col, VPXMAX(BLOCK_8X8, bsize),
-                         ctx, &decision);
+    vp9_denoiser_denoise(cpi, x, mi_row, mi_col, bsize, ctx, &decision);
     // If INTRA or GOLDEN reference was selected, re-evaluate ZEROMV on denoised
     // result. Only do this under noise conditions, and if rdcost of ZEROMV on
     // original source is not significantly higher than rdcost of best mode.